Mountain Hemlock grows in the following 8 states and provinces:

Information about Mountain Hemlock:

The Tsuga Mertensiana is commonly known as the Alpine Hemlock, Black Hemlock, Hemlock Spruce as well as Mountain Hemlock.

The currently accepted scientific name for mountain hemlock is Tsuga
mertensiana (Bong.) Carriere . Mountain hemlock in the
Siskiyous from the Oregon-California border south were recently
classified as Tsuga mertensiana spp. grandicona Farjon, in recognition
of the generally larger cones of trees in this region . All others
are classified as Tsuga mertensiana spp. mertensiana. There are no
recognized varieties or forms. Mountain hemlock will hybridize with
western hemlock (T. heterophylla) .

Mountain hemlock occurs along the crest of the Sierra Nevada; the Coast
Ranges and Cascade Range in Oregon; the Cascade Range and Olympic
Mountains in Washington; the northern Rocky Mountains in Idaho and
western Montana; the Insular, Coast, and Columbia mountains in British
Columbia; and in southeast and south-central Alaska . In
California it is also locally abundant in the Klamath Mountains. The
extreme southern limit of mountain hemlock is near Silliman Lake in
Tulare County, California .

Mountain hemlock commonly occurs as a dominant or codominant in
high-elevation alpine or subalpine forests. In western Washington and
Oregon, the mountain hemlock zone is the highest forested zone .
Mountain hemlock is often codominant with Pacific silver fir (Abies
amabilis) . One of the most widespread mountain hemlock
communities is the mountain hemlock-Pacific silver fir/big huckleberry
(Vaccinium membranaceum) type found in British Columbia and the Oregon
and Washington Cascades. In the Rocky Mountains, the mountain
hemlock/beargrass (Xerophyllum tenax) habitat type is generally found on
south slopes and is characterized by a high cover of beargrass with big
huckleberry and grouse whortleberry (V. scoparium) as common associates.
A similar Pacific silver fir-mountain hemlock/beargrass association is
found in Oregon . Published classifications identifying mountain
hemlock as a dominant or codominant are as follows:
Forest types of the North Cascades National Park Service complex .
Preliminary plant associations of the Southern Oregon Cascade Mountain
Province .
Preliminary plant associations of the Siskiyou Mountain Province .
Plant association and management guide for the Pacific silver fir zone .
Forest habitat types of northern Idaho: A second approximation .
Classification of montane forest community types in the Cedar River
drainage of western Washington, U.S.A. .
Preliminary forest plant association management guide. Ketchikan area,
Tongass National Forest .
Subalpine plant communities of the western North Cascades, Washington .
Alpine and high subalpine plant communities of the North Cascades Range,
Washington and British Columbia .
Fire ecology of western Montana forest habitat types .
Forest vegetation of the montane and subalpine zones, Olympic Mountains,
Washington .
Natural vegetation of Oregon and Washington .
The forest communities of Mount Rainier National Park .
Plant associations of south Chiloquin and Klamath ranger districts--
Winema National forest .
Vegetation and environment in old growth forests of northern southeast
Alaska: a plant association classification .
Forest habitat types of Montana .
Preliminary classification of forest vegetation of the Kenai Peninsula,
Alaska .
Preliminary forest plant associations of the Stikine area, Tongass
National Forest .